Can't answer your question about how much free area is needed to keep from overheating or what gage wire becomes unworkable to get it formed to fit. Kind of sounds like something in the 10-12 wire spacing per inch is about right and appears that is about the wire spacing mentioned in the other thread. I'd want as thick a wire as I could form if its purpose is to deflect rocks.

 

92,000 miles and mine still works fine. I road to Alaska and back and only problem was I had to rinse it out a couple of times but I all so had to do the whole bike. Only road trip I ever washed my bike on and I had to was it at least 4 times.

 

Same principal is used to select the vents in your central A/C...

I believe the other thread had some good info given, don't know how much more you could expect from what I remember being stated there. As for the mud flap, not really sure why you'd think it would stop or impede air flow. I wouldn't think the flap would impede that much...

 

ok guys, you all have good valid points. I guess I'm going with majority rules and I'm going to install it sans a screen and see how it goes! Thanks for the replies!

 

I wouldn't think a mud flap would impede air flow too much. The gravel will be deflected and drop, but the air would still flowaround and under it. You could even drill small holes in the flap and it would flow a little better. As far as the screen, we used to use what we referred to as "rabbit wire" on the front openings of 180-mph
porsche 911s at the various IMSA races in order to prevent tire "clag" and other track debris from taking out our oil coolers. I had a Ferrari puke a motor right in front of me one time and pieces of the valve train were coming out of his pipes. When I got back to the pits one of those pieces had lodged in the screen and torn it, but did not penetrate and harm the cooler. It had little impact on oil temp, of course we had 22 quarts in the system, but it would take a little downforce off the front end due to more frontal area I guess, just like taping the openings. I would think it would serve you well enough, and painted it would look allright on the bike.

 

I would look for a stainless or aluminum expanded metal grating such as this:

http://www.mcnichols.com/products/expanded

Comes in different sizes....usually easy to work with and mount,,,,not very flow restrictive.(depending on size)

The aluminum looks good but may flex a little if hit.

 

In terms of the free area ratio, it is very simplistic and misleading to assume a 50% ratio equates to 50% air flow, that is simply not the case. In fact, I would suggest that you would be closer to seeing no reduction than you would to seeing a 50% reduction. What will happen is that in the area of the screen the air will accelerate through the screen and then decelerate once it is through the screen. There will be a marginal air pressure increase on the front face of the mesh.

In terms of mechanical strength, providing you leave sufficient gap between the screen and the rad you should be fine (I would suggest 1/2" as a rough guide). By the time the stone has broken through the mesh (if it even does) you will have dissipated that much energy that I doubt there will be sufficient energy left to damage the rad. Worst case you may need to cut another piece of screen and replace. The tensile strength of stainless braid is incredibly high.

In terms if 316 vs 304, agree with above, 316 is stronger but both are perfectly adequate for your application

 

I completely agree with this analysis.

Additionally, even if the screen were to effect the airflow, the oil cooler's efficiency is dependent on more than simply airflow. The oil cooler's design, size and construction will limit the amount of heat that can be transferred through it. The heat that is transferred through the cooler is carried away by the airflow through it, but it doesn't take much airflow to carry the heat away. Additional airflow beyond the minimum necessary doesn't do much to increase the efficiency of the cooler.

A couple years ago I did some pretty structured and comprehesive testing on the effects of both engine cooling fans and oil cooler fans as they relate to modern HD's. I even wrote a 21-page white paper documenteing my findings. During that testing I played with different airflows through the oil cooler and found that increasing the airflow (beyond a nominal minimum baseline) had no measurable effect on the oil temperature during otherwise identical test conditions.

Based on what I learned relative to airflow effects on oil cooling during my testing, I could say with a fairly high degree of confidence that installing a screen as you have described in front of the oil cooler will have no measurable effect on your oil cooler's efficiency.

 

This is the best answer I've seen yet.

 

Any way to mount the cooler a bit higher on the down tubes and eliminate the rock exposure? What does the rock exposure do to your voltage regulator?